This project is aimed at the preparation of monodispersed microspheres of metabolizable materials in the size range of 10 to the zero power to 10 to the 2nd power millimicron for medical application. The major phases of the investigation are (1) Design and development of a suitable apparatus for microsphere production. (2) Study of the effect of operating conditions of microsphere production on the quality of the microspheres in terms of contamination, toxicity and radioactive stability. (3) Development of optimum labelling technique of the microspheres using radioactive isotopes and (4) continued study of droplet formulation by forced vibration.